220 COMPARATIVE ANATOMY AND PHYSIOLOGY. 



of a corresponding junction on a neighbouring 

 filament (Fig. 95 ; A) ; and in this way the several 



filaments are connected 

 together. But the concre- 

 scence of the constituent 

 parts of a gill does not end 

 with the union of the 

 neighbouring filaments, the 

 ascending and descending 

 portions likewise become 

 connected with one another 

 by iiiteriamellar junc- 



i! '' 





Fig. 95. A, Part of three gill filaments of Area, showing the large 

 ciliated junctions ; B, transverse section of a portion of an outer 

 gill plate, with solid iuterlamellar junctions and large vertical 

 vessels of Anodon ; c, a more highly magnified view of B. (After 

 E. HolmanPeck.) 



tioiis (Fig. 95 ; B and c), and the bridges of union that 

 were primitively ciliated become fibrous and solid, till 

 at last we reach the continuous plate-like arrangements, 

 which are channelled by spaces, or by definite vessels 

 which lie outside the primitive blood-carrying hollow 



